1. Field of Invention
The present invention relates to hydroelectric generating facilities which may be constructed in conjunction with, or installed as a replacement for, radial water control gates. The hydroelectric generating apparatus disclosed herein may be particularly advantageous for generating power at submergible radial gates, examples of which were constructed at Meldahl Locks and Dam, New Cumberland Locks and Dam, Markland Lock and Dam, and McAlpine Lock and Dam on the Ohio River and Marseilles Lock and Dam on the Illinois River in the USA. The hydroelectric generating facilities and the methods of installation disclosed herein have many potential applications where preexisting gate structures can be converted into hydroelectric plants while avoiding the coffer-damming, dredging, excavation, geological and hydrological risk, and concrete construction associated with traditional hydroelectric generating plants. While a number of hydroelectric plants have been developed using technology as described in U.S. Pat. Nos. 4,755,690 and 4,804,855 to Obermeyer and U.S. Pat. No. 6,281,597 B1 to Obermeyer et al, and which also exploits existing water control structures; the herein disclosed hydroelectric generating art provides several additional advantages including, at certain projects, fuller utilization of all available head, greater power output per gate bay or module, and increased convenience of lifting and lowering the modules to switch between flood passage and hydroelectric power generation modes.
2. Description of Related Art
Various efforts have been made and ideas put forth to develop commercially viable prefabricated hydroelectric generating plants for installation at existing water control structures and which can be lifted above flood level so as to not impede flood flows and thus exacerbate upstream flooding. Some of the prior art apparatus has been designed to fit preexisting stop log slots associated with large scale water control gates as disclosed in U.S. Pat. No. 4,755,690 to Obermeyer, U.S. Pat. No. 4,804,855 to Obermeyer, and U.S. Pat. No. 6,281,597 B1 to Obermeyer et al. These prior art designs have required sill elevations below tailwater elevation in order to utilize all of the available head. Additionally, new large capacity cranes may be required in order to lift the apparatus for servicing and for passage of flood flows. U.S. Pat. No. 4,319,142 to Mayo et al discloses an apparatus which can utilize all of the head at certain preexisting structures, but which may be relatively heavy, large, expensive and possibly not able to be lifted above maximum flood elevation. U.S. Pat. Nos. 4,165,467 and 4,170,428 to Atencio discloses a radially movable turbine generator apparatus which may be too heavy to be supported by preexisting structures and which may have an excessive overall length. A generating assembly that replaces a radial gate should be of limited upstream-downstream dimension. It should not extend so far upstream that, when in its lowered position, it would interfere with or prevent placement of emergency shut-off bulkheads nor, when it is in its raised position, interfere with overhead structures. It should also not extend so far downstream (in its generating position) that, when raised, it would interfere with flood flows or be impacted by waterborne debris.